1. Field of the Invention
This invention relates to an optical card recording/reproducing apparatus wherein such data process as an encoding process or data transfer is made during an access operation or the like.
2. Description of the Prior Art
An optical card-like recording medium has a recording capacity several thousand to ten thousand times as large as that of a magnetic card. However, it cannot be re-written the same as an optical disc. Its recording capacity is so large, typically 1 to 2M bytes, that it is considered to provide a wide application range as a bank deposit book, portable atlas or shopping prepaid card.
Also, since it cannot be re-written, the optical card is considered to be applied to a personal health control card in which data are not allowed to be altered.
Various kinds of such optical card have been already suggested. For example, an optical card disclosed in the publication of Japanese patent application laid open No.37876/1988 is shown in FIG. 1.
As shown in FIG. 1, in an optical card 1, ID parts 4A and 4B contain information showing addresses corresponding to respective tracks. To parts 4A, 4B are recorded so as to be able to be read out in the directions opposite to each other and are provided in both end parts of an optical recording part 3. Recording part 3 has a plurality of tracks 2 parallel with each other and a data part 5 for recording data is provided between these ID parts 4A and 4B. Therefore, for example, when the optical card 1 is moving from left to right in the track direction in FIG. 1 with respect to an optical head, the left side ID part 4A will be read out and, when it is moving from right to left, the right side ID part 4B will be read out so that the track address information corresponding to the track may be identified. The above mentioned ID parts 4A and 4B are provided in the positions inside for fixed distances (for example, of 4 mm) from the card ends in order to prevent the influence of a flaw or stain at the card end and to better stabilize the relative moving speed in the track direction of the optical card 1 and optical head. By the way, the ID parts 4A and 4B are pre-recorded in advance when the optical card is made.
The optical card recording/reproducing apparatus of a prior art example using the above mentioned optical card is formed as shown, for example, in FIG. 2.
So that an optical head 12 may relatively move in the direction parallel with the track of the optical card 1, a controller 11 is connected with a motor servo circuit 13 for moving the above mentioned optical card 1, an optical head driving circuit 14 relatively moving the above mentioned optical head 12 in the direction intersecting at right angles with the track of the optical card 1, a focus & track servo circuit 15 driving an objective lens within the above mentioned optical head 12 in the focus and tracking direction and making an incident light always as focused follow the track of the optical card 1, a laser driving circuit 16 controlling the above mentioned optical head 12 in order to write data into the optical card 1, an error detecting & correcting circuit 18 detecting and correcting errors in the data read out of the above mentioned optical head 12 and demodulated by a demodulating circuit 17, a data buffer memory 19 temporarily memorizing the data transmitted from a host computer (not illustrated), a data encoding circuit 20 adding redundant data for detecting and correcting errors to the above mentioned data and a track buffer memory 21 for temporarily memorizing the encoded data to control them to record/reproduce data.
The operation of the optical card recording/reproducing apparatus of such prior art example in recording data shall be explained with reference to the apparatus in FIG. 2 and the flow chart in FIG. 3.
In recording data in the optical card 1, first of all, in the step S1, the controller 11 receives a command from the above mentioned host computer. It is interpreted to be a command to record data. Then, in the step S2, the data to be recorded are received from the host computer and are temporarily memorized in the data buffer memory 19. Then, in the step S3, the data, for example, for one track are read out of the data buffer memory 19 and are encoded by adding redundant data for detecting and correcting errors by using the data encoding circuit 20 and the encoded data are temporarily memorized in the track buffer memory 21.
Then, in the step S4, the controller 11 calculates the moving amount of the optical head 12 from the track number in which the optical head 12 is now positioned and the objective track number to be recorded transmitted together with the above mentioned command from the host computer and instructs the optical head driving circuit 14 to relatively move the optical head 12 in the direction intersecting at right angles with the track of the optical card 1 and, in the step S5, it is judged whether the above mentioned relative movement has ended or not. Then, in the step S6, the motor servo circuit 13 is instructed to relatively move the optical card 1 so that the optical head 12 may relatively move in the direction parallel with the track of the optical card 1.
Then, in the step S7, the controller 11 monitors the signals from the motor servo circuit 13 and judges whether the relative moving speed of the optical head 12 and optical card 1 is constant or not and, in the step S8, the ID part 4A of such optical card 1 as is shown in FIG. 1 is read out by using the demodulating circuit 17 and error detecting & correcting circuit 18. Then, in the step S9, the track number of the above mentioned read ID part 4A and the objective track number to be recorded are compared with each other. In case they are different, the process will proceed to the step S10 in which the motor servo circuit 13 is instructed to stop the relative movement of the optical head 12 and optical card 1. The operations from the step S4 to the step S9 are repeated again.
In case the track number coincide with the objective track number to be recorded, the process will proceed to the step S11 wherein the above mentioned encoded data to be recorded are read out of the track buffer memory 21 and a high output recording light beam is output as modulated in response to the above mentioned data from the optical head 12 through the laser driving circuit 16 and is controlled to record the data in the above mentioned objective track. In the step S12, the motor servo circuit 13 is instructed to stop the relative movement of the optical head 12 and optical card 1. Further, in the step S13, a fixed matching time is waited to perfectly stop the optical card 1.
Here, in the step S14, it is confirmed whether the data have been recorded in all the objective tracks required from the host computer or not. If they have been recorded, the recording of the data will end. If the recording is not yet completed in all the objective tracks, the process will proceed to the step S3 wherein the data to be recorded in the next track are read out of the data buffer memory 19. The operations from the step S3 to the step S14 are repeated. Thereafter, the operations for the number of tracks required from the host computer are repeated to end all the recording of the data.
However, generally, as compared with a recording/reproducing apparatus using such disc type recording medium as an optical disc, in an optical card recording/reproducing apparatus, for example, an access operation for an optical head to reach an objective track takes a longer time and, therefore, the time from a command to record data is received until the recording in the medium is started is also longer and should be improved.
Particularly, in such optical card recording/reproducing apparatus of the prior art example, as described above, the process from a time when a command to record data is received until the data are recorded in a medium is made in series and, therefore, the time for recording the data is undesirably long.
On the other hand, in the publication of Japanese patent application laid open No.131317/1987 is suggested a technique of reading data out of an optical card and transferring them to a host computer.
In the optical card apparatus, in reading out data, an optical head is made to seek a target track on an optical card, then the optical card is driven at a constant speed and information is read out of a data part in which the information is recorded. The data read out are demodulated and are stored in a buffer memory part. After the data are stored, a host computer then transfer them, and the data are transferred to the host computer.
Also, in the optical card apparatus, after the optical card is moved in one direction and reading the data out of a linear track is completed, the optical card moving direction is revised and, after a constant speed is reached, the next reading is made. In the apparatus of the prior art example, in preparation for the next reading, the data stored in the buffer memory part are transferred until the optical card reaches a constant speed from the turned drive so as to improve the efficiency of the data transfer.
However, in this optical card apparatus, without correcting errors of the read out data, the data are transferred to the host computer as an external apparatus and further, since the optical card is turned and driven until just before the constant speed is reached, the data transfer takes time. Therefore, on the host computer side, if the data error correction is included, much time will be required for the communication with the optical card apparatus. Thus, in the optical card apparatus of the prior art example, the time for access to the host computer is relatively long while, on the host computer side, the time for other processes is short.